This invention relates generally to optical plummets, and, more particularly, to an azimuth reference assembly for use with an optical plummet to permit development of a reference azimuth as the observing station with respect to an underground or elevated object which is being referenced by the optical plummet.
In any area in which an optical plummet is utilized for precise vertical alignment of either an elevated or underground target or object it may also become necessary to increase the use of the optical plummet by making it available to align a reference mark on the target or object to both the local vertical and to the azimuth plane passing through the target being aligned. For example, this problem arises quite frequently in the construction of mining shafts, in the laying of underground pipes, in the axial orientation of bore hole tiltmeters and in the referencing of targets located in space.
Heretofore, such alignment problems relied heavily on inaccurate trial and error procedures. For example, one way of establishing azimuth down a shaft was to use two plumbed lines along the azimuth line. These were observed at the surface and with the use of a theodilite an azimuth value was "backed in" at the surface from visible references. Not only did these alignment measurements prove to be extremely inaccurate and therefore create many of the construction problems encountered today, but also such methods of the past proved to be a costly procedure for yielding results which, in many instances, were virtually useless.